Many people prefer a purebred dog to a mutt because they know what they're getting. With a purebred dog, they can look at the breed standard and get an idea of temperament, exercise and grooming requirements and size. Unfortunately, what they can also get an idea of is what illnesses and conditions they should be prepared for down the road.

Most breeds that are registered with the American Kennel Club also have a list of inherited conditions that they are predisposed to. Whether that list contains a few items or many often depends on how old the breed is, and how breeding has been done over the years.

Hip dysplasia is a degenerative condition that impacts mostly large breeds. German shepherds, Great Danes and dogs in the retriever and mastiff categories are known for developing the condition as they age. As the dog ages, there is a progressive degeneration of the tissues, muscles and ligaments that hold the hip joint in place. Most of the dogs that develop the condition do so as they are approaching the far end of middle age, though it has been known to manifest in puppies that are only a few months old.

As the condition develops, the owner will begin to notice the dog having difficulty moving or extending the rear legs. Their gait may chance, especially when running. It is often accompanied with morning stiffness, and as the disease progresses the dog may require help sitting and standing.

Since dogs are often bred before the disease begins to show itself, many puppies are born to parents who are genetically disposed to the condition. This passes it on to the pups, but there is no guarantee that the puppies will be effected. Dogs with hip dysplasia can often go on to lead long and comfortable lives with proper care. A proper diet and exercise regimen when they are young will help keep the body strong enough to fight the effects of the disease, while an obese, unhealthy dog will be more likely to suffer severe symptoms.

For those that do develop the disease, there are surgical option available. Often, it can be monitored with medicine and environmental therapies such as massage, orthopaedic beds and low-impact exercise.

Progressive retinal atrophy, or PRA, is one of a number of inherited conditions that impacts the dog's sight. Mastiffs and huskies are particularly vulnerable to this degenerative disease that will ultimately result in blindness, although there are a number of similar diseases that can be found in other breeds.

By the time most people notice there is something wrong, the disease has already progressed to partial or night blindness. The first external signs is a strange glow coming from the eyes, or an unnatural shiny appearance. Supplements can sometimes be given to slow the progression of the disease, but the end result is typically blindness as soon as a year after the first signs are seen.

Fortunately, and unlike hip dysplasia, PRA is not a painful condition. many dogs are able to adjust to the progressive and slow loss of sight, and can adapt fairly well to the condition. Dogs that have a well-established routine and are kept in familiar surroundings will continue to live a long and happy life, depending on their other extremely keen senses to fill in what they have lost in their sight.

There are DNA tests available that will look for the genetic markers that indicate the presence of inherited conditions like PRA. If these conditions are discovered, notifying the breeder as well as the AKC can help prevent more puppies from being born in the same line with the same genetic conditions. Weeding out the genetic imperfections within a breed will only make it healthier, but removing all imperfections is, sadly, simply unrealistic.